Don't corrupt categories/langlinks with new types

Parsoid changed these types from mw:WikiLink/{Category,Language}
to mw:PageProp/{Category,Language} in I0f0a826c. We had previously
added support for them in 4d91e4ed but code overwrote the new types
with the old ones on the way out, triggering the DOM corruption warning.

Change-Id: I768ec2ffd623e5a01f18959277786697603a97f0
Merge "Don't corrupt categories/langlinks with new types"